1. Field of the invention
This invention relates to a wrenching tool useful for removal of collars of fasteners, and in particular, to a tool with a telescoping key holder for ease of replacement of keys of the tool.
2. Brief Statement of the Prior Art
Frangible fasteners are used extensively in the aerospace industry. These fasteners employ a threaded locking collar which is joined by a notched neck to a wrenching ring which shears from the collar when the applied torque exceeds a predetermined torsional loading. Often the threaded locking collar has an upset portion, usually a slightly elliptical shape to provide a frictional spring lock that prevents the collar from spinning off in the event that the residual tension on the fastener is lost.
These fasteners are applied with wrenching tools which engage the wrenching ring to apply the threaded collar and twist the wrenching ring from the threaded collar when the predetermined torsional loading is exceeded.
It is frequently desirable to loosen or remove threaded locking collars from assembled fasteners. In my prior patents, U.S. Pat. Nos. 4,862,773 and 5,095,779, I have disclosed power driven and manual tools which have a collet chuck to grip and remove fastener collars.
These tools are provided with a central, hexagonally flatted, stationary key which is received in a hexagonal recess in the end of the pin of the fastener to immobilize the pin. The power tool disclosed in my prior patent U.S. Pat. No. 4,862,773 uses a quick disconnect key having a detent system which is disclosed in my prior patent U.S. Pat. No. 4,538,483. While this detent mechanism facilitates replacement of worn or broken keys, difficulty is experienced when a key breaks within the collet chuck leaving a broken end which is not readily accessible.